Reforming process wherein the temperatures in and temperature drop across a reactor or reactors are controlled



N. cz.` CARTER 2,955,080 REFORMING PROCESS WHEREIN THE TEMPERATURES 1N'AND TEMPERATURE- Oct. 4, 1960 Filed July 31, 1958 A TTORNE YS UnitedStates Patent Op REFORMING PROCESS WHEREIN THE TEMPERA- TURES INANDTEMPERATURE DROP ACROSS A REACTOR OR REACTORS ARE CONTROLLED NormanC. Carter, Sweeny, Tex., assigner to Phillips Petroleum Company, acorporation of Delaware Filed July 31, 1958, Ser. No. 752,214

'1'2 Claims. (Cl. 208-63) This invention relates to reforming. In one ofits aspects, the invention relates to reforming of a hydrocarbon stream,containing naphthenic hydrocarbon, in which stream the proportion ofnaphthenic hydrocarbon is controlled thereby controlling thetemperatures in the reactor in which the reforming reactor is takingplace. In another of its aspects, the invention relates to the controlof the temperatures in and temperature drop across a reactor or reactorsby controlling the naphthenic content of a charge fed to said reactor orreactors, in the case of a plurality of reactors, adjusting thenaphthcnic content of the charge to each reactor independently of thecharge to any other reactor. In a further aspect,

`the invention subjects to a separation process, for example naphthenemolecules in the stream. In the dehydrogena- Y tion process orrreaction,there Yis formed hydrogen believed to be at least initially in nascentform. I have found that by controllingrthe Yproportion of naphthenichydrocarbon in Vthe charge tova reforming reaction zone Iv can controlthe temperature in said-zone. Moreover, YI

40. Light hydrocarbon '.boilingbelow about .15G-5F. is rehave discoveredthatin so doing, especially inthe case of j a plurality of reactionzones yoperated in series, I can con-V siderably decrease .very.advantageously the coke laydown on the catalyst which is employed. Thisis due to the formation of fresh hydrogen, likely in nascent form, whichis formed on the catalyst from the freshly introduced naphthenes, as -inthe concentrate above mentioned. I Y have further found thatfbycontrolling thenaphthenics content of the stream to -each of severalVreactors I vcan obtain a lower temperature dropiacross each of thereactor beds thus obtaining anarrow spread between the reactors inlettemperatures. Since the reaction converting a naph-V thene to anaromatic is endothermic, it will be obvious from considerations hereinthat the temperature of the charge to, say, a first reactor need not beas high when ,j 2,955,080 .Patented Oct. 4, 1960 ICC reduce the overalltemperature drop through a series of reactors employed in reforming yahydrocarbon.

Other aspects, objects and the several advantages of this invention areapparent from a consideration of this disclosure, the drawing `and theappended claims.

Accordingto this invention, the temperature drop across a reforming zoneis controlled by adjusting the content ofnaphthene in the feed to saidzone. Further, according to the invention, there is provided a method ofcontrolling the temperature andthe temperature drop in and acrossseveral reformingzones by controlling the proportion of naphtheneconstituents of a `charge material as it is fed serially through saidzones. Further, according to the invention, a ynaphthenic hydrocarboncharge is solvent extracted to obtain a naphthenic vconcentrate and a-rafnate containing some naphthenes, the rafnate is reformed in areaction zone, a portion of naphthenic con.- centrate isadded `to .theveffluent from said zone and Ythe mixture thus obtained reformed furtherin a secondzone. Similarly, before reforming further in a third zone,another portion of naphthenic concentrate can be added to the eflluentVfrom the second reforming zone and so on.

It is within the scope of the invention to adjust the naphthenicconcentration of the feed to a zone Vor to any zone in a series of zonesby feeding from an outside source a naphthenic hydrocarbon to be-chargedto a given zone.

The invention will now be set forth, described vand illustrated withrespect to the reforming of a naphthenic gasoline. It will be understoodthat somewhat heavier hydrocarbon fractions can be reformed in similarmanner. Further still, it will be understood that there can be added tothe feed to the method externally available naphthenic materialanngnwhichlare Vincluded methylcyclohexane, dimethylcyclohexane and/orethylcyclo hexane., etc. fl Y Referring now to'thejdrawing, alIrraphthenic gasoline havinganend pointof. 510 Ffischargred atthe rateof 79() barrels perhour via'linejStoprefractionation A.

moved at about A120 barrels per hourgviaV 'line 6 for :further use asdesired. Heavy hydrocarbon boiling above about 400 F. is removed atabout ftQjbarrels per hour via line '7 for further use .asAdesired..--Ah-ydrocarbon stream-containing -naphthenicsis remeved-vialine l0 at therate of 630 barrels per hour. About 70 barrels yper hour-Yof this Cut, boiling betweenlabehtf 15o-40,0912., is charged via line11 to the conventional-type solvent extraction zone B. Theremainderof.the stock in line 10 at the fate Of about '5160'barrelsPsrheur'byipasses the extraction zone via lineY 12.V -Infzone B,va Anaphthenie concentrate containing 60'toj75jyolurnelpercentnaphthenics is produced and removed vialine 14-at-the rate of 40 barrelsper hourY and'islprocessedj'asdescribed below.

A stream lean in naphthenics isi-removed from the top fof j zone Bbyline 12 at the rate' off30'ba`rrels per hour and a portion of thenaphthenics is'added to a later reactor Vmore effective operation of thesystem.

It is an object of this invention to reform a hydro- Ycarbon. Itis afurther object of this invention to Yprovide a method of controllingthetemperature in a reactor or Vina series of reactors employed in ahydrocarbon reforming operation. It is a further object of thisinvention =to is combined with the 560 barrels of hydrocarbon from line12." The combnedmsitre'am' 'containing 36 to 45 volume percentnaphthenics is charged via lines 13 and 16 along with recyclehydrogenfrom line 1'5 added in suiicient quantity to produce a mol ratioof Iig/hydrocarbon of about "-7: 1l to 10:1 to heater 17. The combinedstream after passing through the heater 17 is charged via line 18to4reactor119. V'The Vinlet temperature to reactor 19 is 890 to 940 F.,with a AT thereacross of 60 to F. Tiheefuent from reactor 19 passes outvia line 20 and has added thereto, at the rate of Vabout 20 barrels perhour, ay naphthenics concentratestream from line 14, abovefdescribed,which is quite rich in naphthenics "and which controls theA'T acrossVthe bedof reactor 2 3 to which 4it is yfed by -Wayofheater k2,1 andpipe A2.2'. Elle inlet'temperature'to ra'c'tor'z is 875 to 925 F., witha 35 to 45 F. temperature'drop across the bed in reactor 23. The eiuentfrom reactor 23 is passed via line 24 and thas added theretoaboutZObarrels per hour of the rich t 4 s Y other solvents which can be usedinclude monomethyl and monoethyl ethers of ethylene glycol anddiethylene glycol, methyl carbitol, etc. f

'I'he catalysts which will dehydrogenate naphthenes and the conditions.o f'neatment can be made.A Solvents which -can be employed inthe-solventextraction stepof the invention are well known-inVV thejart.: Iii-theexample described herein, -conventionald-furfrural solvent is emtionsoftemperature in abuses ,thes'leve 501W; tof. message boa/@Yee u uns;

`naphthenic stream introduced'via line 35.A 'The combined 5 reformhydrocarbons are also well known in the art. .stream passes out via lineY24 to heater 25 and is charged In the example described, the catalystis a platinumyto reactor 27 via line 26. The inlet'temperature toalumina-halogen catalyst; the platinum content being in reactor 27 isabout 870 to 920 R'With a temperature the range of`0.05 to 1.5 weightpercent5and the Yiuorine drop across the bed of the reactor of about to25 F. content being less than about 3.0 weight percent based on Efuentfrom reactor 2.7 isgpassed out via line 28 and 10 dry alumina. condenser29 and pipe 30 to separator 31 wherefromY YIt will beA obvious to oneskilled in the art in possession vunstabilized reformate is removed forfurther processing of this disclosurethat it is within the scop'eof theclaims via line 32. A hydrogen-rieb gas isremoved via 3'3 and to contactthe proportion of naphthenic hydrocarbon in net hydrogen 1s recoveredvia 34.1 The remaining hydrothe feed to a givenY reactor lresponsive tothe temperature sentream farrecycle 1S compressed and returned {01116;15in said reactor at any desired,pointtherein. Thus, it is feactm' Systemby Way Ofl .P1Pe 15 Which miams a evident upon reading this disclosurethat a proportioning OmPfeSSOf 36- Y Y I, Y YL pump or other means canbe used to dose in, as it were, 5 ghe ows of naphuemc nntfmtoeactors 23the desired proportioirof naphthenic hydrocarbon re- 'in 271 are notncessaly equatl qultles Insome opera' 20 `sponsive to energy supplied tohePlrlmP, 59W 0f. the zgns ess.may e Se? 9 rerac or, an, mofa-tomadorenergy being controlled by the temperature at said poin and vice versa.Y Y Y. Y. Y It will be seen from the fore o' desc` ti th t m thereactor' 's l f Y g .lg Y 'np on a The tabulation below specificallycompares a convenaccording to the methodof my invention, the volume per-,d

onal reformingroperation with the operation in accordcent of naphthemcs1S Colm-oued m the feed, -each of ance withm inventionn In cacho erationtheh dro en the thi-ee reactors and, thereforefin the reactors. This t hdr 1 tf 7' t l p Th g. etectsa lower temperature diierence across thebeds of o y ocar on m0 ra .lo 1S o' e same re ormmg each of thereactorspwducmg the narrow spread be catalyst, as above described, isused in Vall of the reactors. tween Vthe inlet temperature of any oneVreactor-and any The $311.16 naphthenfc gasolme 1s charged to each: tothe other reactor in Vthe system l Y conventional operation at the rateof 630 barrels per hour Y The following table of information constitutesa part serially through 211 me? le-'itOIS and CODHPDEZJ of theoregoingexample. It will be noted that designa- Volume Percentnaphthemcs; and t0 me. OPSFaAlOII 0f ml' 4tions at the top of eachcolumn apply to respective parts DVCBOD at the ,Tate 0f 590 bafels Pel'hour serially of the system. e Y through all three reactorsV andcontaining 40.4 volume A Iable Unit onLine No i--- 5 e Y 7 in 12V n i412' amas/hour 79o 120 to 56o 7o Y 4o so Percent (Voi.) Naphthenics .s37.5-4s.s ans-116.8 60-75 1.7-9.3 BbiaNnpmhpnm Y Y ases-294.8 21o-26226a-32.8 24-30 42.3-2.8 Pressure, p si a Top,

Bottom Y Temperature, F

Top-

Botfnm Y Hz, MM s.c.f.lday Platormate, b./h Mol percent H3. Y C1 to C5HIC, Mol Percent4 Y Boiling Range, F.. 7150 ft0ov 15H00 1504100 15o-40015o-400 15H00 Unitor Line Na...y Y' `is 'i "n Y i9 A2.a, Y 21l si A 34 p32' Y 1s ais-44.8

Bbls. N aphthenics 212. 3-264. 8 Pressure, p s i g Y 450 Top 20-60.Bottom 25-65 Temperature, F Y 100 K op 25u-28o 89H40 575-925 870-920Boum Yiso-51o 830-840 sui-880 855-895 11 MM s.c.f./day Y K Y s, 5-12Platformate, b./li ,1569-600 s Mol Percent FT, 80-95 80-95 Y C; to C5HIC, Mol Percent..- Y 20-5 not A20-5 Y *l Y Y ported :Boiling Range, F15G-40,0

It will be evident to one skilled in the inYV possession percentnaphthenics, andadding tothe second reactorand Vof this disclosure thatthe operation which has been to the third reactor each ZDYbarrels perhour of the naphdescribed is for purposes of compliance with' the patentthenie concentrate containingvl volume percent naphlaws and practice,thereunder and is Vnot to b'etakenrby thenics, which concentrate wasrecovered from the original way ofV limiting the appended claims; It isclear that 630'barrels perl hour of fresh charge, 111 accordanwlthwithinthe scope of the appended claims somervariation Vmy invention. 'jy V` f f `and modification of the Ynaphthenic charge treated and Afterrunning for equal periods of time, atthe condithe reactors listedbelow,g and Yproducing substantially thesar'nequality` and 4quantity ofreformate in each operation,i.e., 9r2 .5liquidV volumeper- Cent 0fcharge, contipressioigroiiV coke onV the catalyst is Conven- Inventiontional Wt. Percent Coke on Catalyst:

Reactor 19 1. 2 1. 5 Reactor 23.- 2. 4 1. 9 Reactor 27 2 6 2 2 InletTemperature, F.:

Reactor 19 5 905 Reactor 23- 895 900 Reactor 27 880 892 OutletTemperature,

Reactor 19 830 835 Reactor 23 865 860 Reactor 27 875 875 DifferentialTemp., F.;

Reactor 19 85 70 Reactor 23 30 40 Reactor 27 5 17 The differentialtemperatures across the reactors in the operation in accordance with myinvention are 70, 40, and 17, respectively; while by conventionaloperation the differential temperatures are 85, 30, and 5, respectively.The coke deposited is considerably less when operating in accordancewith my invention as shown in the above table. Further, the cokelaydowns on the catalysts in the second and third reactors, for the samelength run in each operation, are less when operating in accordance withmy invention. In conventional operations, the coke contents of thecatalysts in the second and third reactors are the bottlenecks requiringshut down of the process. My operation minimizes the heavy coke laydownsin the second and third reactors allowing longer on stream time for theoperation.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure, drawing and the appended claims to theinvention, the essence of which is that the naphthenics concentration ina charge to a reforming zone is controlled thereby -controlling thetemperature or temperature drop in and across said zone and that in aplurality of zones through which a charge is fed serially the eiuentfrom a lirst zone is admixed with a naphthenic material to increase itsnaphthenic content before it is passed into an ensuing zone, etc.,substantially as set forth and described herein.

I claim:

1. A method for lthe reforming of a naphthenic gasoline hydrocarbonfraction also containing non-naphthenic constituents which comprisesfeeding said fraction as the sole hydrocarbon feed stream to a reformingzone and controlling the temperature of said reforming zone in whichsaid hydrocarbon fraction is reformed to a desired predeterminedtemperature by varying the proportion of naphthenic hydrocarbon in thecharge to said zone responsive to the temperature of said zone tomaintain said desired predetermined temperature.

2. A method of operating a plurality of reforming reactors to which anaphthenic gasoline hydrocarbon charge also containing non-naphthenicconstituents is fed in series as sole hydrocarbon feed stream charged tosaid reactors and in each of which reactors it is desired to maintain,respectively, a predetermined temperature which comprises varying thecharge to each reactor and varying the charge to each of said reactors,respectively, responsive to the predetermined temperature in each ofsaid rectors to contain a proportion of naphthenic hydrocarbon adaptedand suiiicient to control the temperature of each reactor to which it ischarged to maintain in each reactor, respectively, the predeterminedtemperature desired in each of said reactors.

3. A method for reforming a naphthenic hydrocarbon charge whichcomprises solvent extracting said charge to obtain a naphthenicsconcentrate and a railinate, charging a naphthenics containinghydrocarbon fraction also containing no n-naphthenic hydrocarbon to afirst reforming reaction zone and therein reforming said charge,removing eluent from said reaction zone, varying the naphthenic contentof said etluent responsive to the temperature of a second reformingreaction zone in which a predetermined temperature is being maintainedby admixing said effluent with at least a portion of said naphthenicsconcentrate, passing the admixture thus obtained to a second reformingreaction zone and recovering reformed eluent from said second reactionzone, thus maintaining said predetermined temperature in said secondreforming reaction zone.

4. A method for the reforming of a hydrocarbon charge containingnaphthenic and non-naphthenic molecules which comprises sensing thetemperature in a reaction bed in which reforming of said hydrocarboncharge is taking place and varying the proportion of naphthenicmolecules in said hydrocarbon charge responsive to said temperature.

5, A method of reforming a hydrocarbon charge containing naphthenic andnon-naphthenic molecules which comprises subjecting s'aid charge to anoperation to remove therefrom a naphthenic concentrate, passing saidthus treated charge to a reforming operation, sensing the temperature insaid reforming operation, and proportioning said concentrate into saidthus treated charge responsive to said temperature.

6. A method according to claim 5 wherein the naphthenic concentrate isobtained by solvent extraction of the charge.

7. A method for the reforming of a naphthenic gasoline hydrocarbonfraction also containing non-naphthenic constituents which comprisespassing a portion of said fraction to a heating zone and then to areforming reaction zone, solvent extracting another portion of saidfraction obtaining a naphthenic extract and a paraflinic reiiinate,modifying the portion of said fraction passed to said heating zone inaccordance with a predetermined temperature being maintained in saidzone by incorporating therewith at least a portion of said rainate andpassing the modified heated portion to said reforming reaction zone andtherein reforming said modified fraction.

8. A method according to claim 7 wherein a reforming reaction zoneeffluent is removed from said reforming reaction zone, at least aportion of said naphthenic extract is combined therewith and the thusmodied eluent is passed to a heating zone and then to a reformingreaction zonefor further reforming therein.

9. A method according to claim 8 wherein an eiuent is recovered from thelast mentioned reforming reaction zone, a further portion of saidnaphthenic fraction is admixed therewith, the thus modified efliuent isheated in a heating zone and then passed to a reforming reaction zonefor reforming therein.

l0. A method according to claim 7 wherein the proportion of parafnicranate added to the portion of naphthenic fraction passed to saidheating zone is controlled responsive to a temperature sensed in saidreforming reaction zone.

11. A method according to claim 8 wherein the proportion of naphthenicextract added to the reforming reaction zone eiiluent is controlledresponsive to a temperature sensed in the last mentioned reformingreaction zone.

12. A method according to claim 9 wherein the further portion ofnaphthenic extract which is added to said effluent is controlledresponsive to a temperature sensed in the last mentioned reformingreaction zone.

References Cited in the file of this patent UNITED STATES PATENTS2,335,684 Mayer Nov. 30, 1943 2,630,404 Berger Mar. 3, 1953 2,654,694Berger et al. Oct. 6, 1953 FOREIGN PATENTS y 121,173 Australia Mar. 28,1956 723,785 Great Britain Feb. 9, 1955

1. A METHOD FOR THE REFORMING OF A NAPHTHENIC GASOLINE HYDROCARBON FRACTION ALSO CONTAINING NON-NAPHTHENIC CONSTITUENTS WHICH COMPRISES FEEDING SAID FRACTION AS THE SOLE HYDROCARBON FEED STREAM TO A REFORMING ZONE IN CONTROLLING THE TEMPERATURE OF SAID REFORMING ZONE IN WHICH SAID HYDROCARBON FRACTION IS REFORMED TO A DESIRED PREDETERMINED TEMPERATURE BY VARYING THE PROPORTION OF NAPHTHENIC HYDROCARBON IN THE CHARGE TO SAID ZONE RESPONSIVE TO THE TEMPERATURE OF SAID ZONE TO MAINTAIN SAID DESIRED PREDETERMINED TEMPERATURE. 